The environment of rotating ammunition such as mortar projectiles, shells or other types of ammunition, is characterized, when they are used, by the presence of axial acceleration forces and centrifugal forces. For example, a piece of ammunition in a launcher tube or in a propelling device is subject to axial acceleration forces on leaving the tube and centrifugal forces originating from the rotation movement produced, for example, during the displacement of the ammunition in the tube, by spiral grooves in the inner wall of the tube.
Ammunition normally comprises a priming fuse of an explosive charge carried by the ammunition. The priming fuse comprises one or more safety devices to prevent the explosive charge from being activated by accident during storage or transport operations by persons.
The miniaturization, reliability and reproducibility of safety systems lead ammunition fuse designers to use safety priming devices (DSA) in micro-electro-mechanical systems (MEMS) technology.
MEMS use micromachining techniques on silicon for integrating sensor and actuator functions sometimes combined with electronics. The most common MEMS sensors are accelerometers in airbag, geophone and rate gyroscope applications.
MEMS may combine elements of mechanical, optical, electro-magnetic and electronic technology with electronics or mechanics on semiconductor substrates.
Specifiers, in the ammunition field using MEMS, call for much greater reliability in priming safeties which may sometimes offer common causes of failure.